Vehicle Bumper Crash Box Towing Eyelet Attachment

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Solution Overview

Problem

The attachment of a towing eyelet to one side of a car bumper adversely affects the deformation properties of the crash box due to asymmetrical loading, as existing designs do not allow for stable attachment without compromising the crash box's structural integrity.

Innovation Solution

A tapered crash box with a welded-on cover and a coaxial hole system, featuring an internally threaded sleeve that supports the bumper bar and provides a stable attachment point for the towing eyelet without altering the crash box's deformation properties, allowing for symmetrical loading and minimal impact on crash box deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a towing eyelet is attached to one crash box, then the towing function is achieved, but the deformation properties of the crash box are adversely affected

Engineering Contradiction:
Improvetowing functionVSAvoiddeformation properties
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The attachment system is segmented into separate components: the crash box remains structurally independent while the towing eyelet is mounted on a cover plate attached to the bumper bar. This segmentation allows the crash box to maintain its deformation properties while the towing function is provided by the separate eyelet assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cover plate serves as an intermediary element between the bumper bar and the towing eyelet. It provides a mounting surface for the eyelet while being attached to the bumper bar at a location that does not interfere with the crash box's deformation characteristics.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the towing eyelet is attached directly to the crash box, then the attachment is stable, but the crash box's structural integrity is compromised

Engineering Contradiction:
Improveattachment stabilityVSAvoidstructural integrity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The attachment system is divided into separate functional elements: the crash box for structural integrity and the cover plate with eyelet for stable attachment. This allows each component to fulfill its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The towing attachment function is extracted from the crash box structure and placed on a separate cover plate. This extraction allows the crash box to maintain its structural integrity while the towing eyelet provides stable attachment on its own mounting surface.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If asymmetric attachment is used, then the towing function is provided, but the crash boxes have different deformation properties

Engineering Contradiction:
Improvetowing capabilityVSAvoidsymmetrical loading
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The cover plate design is universal and can be applied to either or both crash boxes without affecting their symmetry. The same attachment mechanism can be used on both sides, allowing for symmetrical loading while providing the towing function where needed.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The attachment system is applied locally on the bumper bar through the cover plate rather than being integrated into the crash box structure. This local application allows for asymmetric or symmetric configuration as needed while maintaining the crash boxes' identical deformation properties.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables stable and symmetrical attachment of the towing eyelet, maintaining the deformation properties of the crash box and ensuring consistent structural integrity, even when only one crash box is equipped with the attachment mechanism.

Implementation Method 1

an internally threaded sleeve welded at least to one or other of the cover and the bumper bar

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP2512840B2Bumper for a vehicle
Publication Date: 2021.08.25 GESTAMP HARDTECH AB
  • EP2512840B2 patent drawingFigure 1~2
  • EP2512840B2 patent drawingFigure 3~4

AI summary

A bumper includes a bumper bar (14) and two crash boxes (11) welded to the bumper bar, one of the crash boxes having an inwardly threaded sleeve (17) serving as an attachment means for a towing eyelet. A mounting plate (13) is welded to the outer end of the crash box, thereby serving as a cover, and to the bumper bar (14). The mounting plate has an indentation with a hole to the edges (18) of which the sleeve (17) is welded and the sleeve is supported against the edge (19) of a hole in the bumper bar at an axial distance from the point at which it is welded to the mounting plate.